We can make a decision based on the two factors listed below. You may enroll for any of the tableau online course and get better understanding on the Tableau and Power BI.

Both Power BI and Tableau are data visualization software that are used in the analytics and reporting domains.
Power BI is a Microsoft offering, whereas Tableau is now a Salesforce product.

Tableau Desktop costs approximately $70 per month, whereas Power BI costs $10 per month. You do not need to be concerned about the cost because no organization will require you to purchase these to work on the project. Both software are available for free for educational purposes. Although we can see that the cost of Power BI is lower, this does not imply that everyone should use it.

The requirement for project-level implementation is also present here. Tableau offers a more dynamic and in-depth level of chart implementation than Power BI. As a result, if your project requires advanced implementation, regardless of cost, you should only use Tableau. Because they will be in discussion with you or your team, the client will pay the cost.

Typically, if your project requires simple project implementation, you can use Power BI to save money. Tableau can hold more data than Power BI, so if you have a lot of data, you should get Tableau.

If you are looking for work, you can learn any of these, but if a client requests it, you must learn the specific software that the client has requested. Tableau is a good general option.