You can change your password when you are logged in to Pinterest by editing your settings.

Change your Password from your Settings
1. Click on ··· the top of Pinterest to open your menu
2. Click on 'Edit settings'
3. Click on 'Change your password'
4. Input your old password and your new password twice
5. Click on Save

How to Reset Pinterest Account Password
If you forgot your password, a link can be sent to you by Pinterest to create a new password and get back into your account.

To reset your password:
1. Navigate to pinterest.com/password/reset on your browser to request a password reset
2. Search for either your email address, name or username to find your account
3. Click on your account
4. Check the inbox of the email address linked to your account for a password reset email
5. Click on the link in the email and enter a new password

https://www.olonix.xyz/2019/05/how-to-change-pinterest-password-fast.html