Making use of https://www.nairaland.com/3381548/how-write-letter-application-job as reference.

The No. 1 has the receiver's address immediately under the sender's address.

The No. 2 has the sender's address by the left, with the receiver's address on the right.

The No. 3 has the sender's address on the right, with the receiver's address on the left - typical Nigerians' style.


Which is the best, and why those formats

I make use of the No. 1 method though.

1.


Your Street Address
City, State Zip Code
Telephone Number
Email Address
Month, Day, Year

Mr./Ms./Dr. FirstName LastName
Title
Name of Organization
Street or P. O. Box Address
City, State Zip Code

Dear Mr./Ms./Dr. LastName:
LETTER OF APPLICATION FOR A (Write what you are applying for )

Opening paragraph: State what position or internship you are applying to; how you learned of the organization or position, and basic information or qualifications about yourself.

2nd paragraph: Tell why you are interested in the employer or type of work the employer does (Simply stating that you are interested does not tell why, and can sound like a form letter). Demonstrate that you know enough about the employer or position to relate your background to the employer or position. Mention specific qualifications which make you a good fit for the employer's needs. This is an opportunity to explain in more detail relevant items in your resume. Refer to the fact that your resume is enclosed. Mention other enclosures if such are required to apply for a position.

3rd paragraph: Indicate that you would like the opportunity to interview for a position or to talk with the employer to learn more about their opportunities or hiring plans. Restate briefly why you're so passionate about the opportunity you're applying for. State that you would be glad to provide the employer with any additional information needed. Thank the employer for her/his consideration.

Yours Sincerely,
(Your handwritten signature)
Your name typed
Mobile number (Not compulsory)

2.


Your Street Address
City, State Zip Code
Telephone Number
Email Address
Month, Day, Year

......................Mr./Ms./Dr. FirstName LastName
......................Title
......................Name of organization
......................Street or P. O. Box Address
......................City, State Zip Code

Dear Mr./Ms./Dr. LastName:
LETTER OF APPLICATION FOR A (Write what you are applying for )

Opening paragraph: State what position or internship you are applying to; how you learned of the organization or position, and basic information or qualifications about yourself.

2nd paragraph: Tell why you are interested in the employer or type of work the employer does (Simply stating that you are interested does not tell why, and can sound like a form letter). Demonstrate that you know enough about the employer or position to relate your background to the employer or position. Mention specific qualifications which make you a good fit for the employer's needs. This is an opportunity to explain in more detail relevant items in your resume. Refer to the fact that your resume is enclosed. Mention other enclosures if such are required to apply for a position.

3rd paragraph: Indicate that you would like the opportunity to interview for a position or to talk with the employer to learn more about their opportunities or hiring plans. Restate briefly why you're so passionate about the opportunity you're applying for. State that you would be glad to provide the employer with any additional information needed. Thank the employer for her/his consideration.

Yours Sincerely,
(Your handwritten signature)
Your name typed
Mobile number (Not compulsory)

3.


............................................Your Street Address
............................................City, State Zip Code
............................................Telephone Number
............................................Email Address
............................................Month, Day, Year

Mr./Ms./Dr. FirstName LastName
Title
Name of Organization
Street or P. O. Box Address
City, State Zip Code

Dear Mr./Ms./Dr. LastName:
LETTER OF APPLICATION FOR A (Write what you are applying for )

Opening paragraph: State what position or internship you are applying to; how you learned of the organization or position, and basic information or qualifications about yourself.

2nd paragraph: Tell why you are interested in the employer or type of work the employer does (Simply stating that you are interested does not tell why, and can sound like a form letter). Demonstrate that you know enough about the employer or position to relate your background to the employer or position. Mention specific qualifications which make you a good fit for the employer's needs. This is an opportunity to explain in more detail relevant items in your resume. Refer to the fact that your resume is enclosed. Mention other enclosures if such are required to apply for a position.

3rd paragraph: Indicate that you would like the opportunity to interview for a position or to talk with the employer to learn more about their opportunities or hiring plans. Restate briefly why you're so passionate about the opportunity you're applying for. State that you would be glad to provide the employer with any additional information needed. Thank the employer for her/his consideration.

.........................Yours Sincerely,
.........................(Your handwritten signature)
.........................Your name typed
.........................Mobile number (Not compulsory)

I make use of number 3.

No. 1 is the updated way of writing formal letter...

No 3 is the most widely used in Nigeria and I always recommend it for any body applying for a job in Nigeria. But if you want to apply for a job overseas, No 1 is the standard format.

Nice

Ok