You can follow the below-mentioned steps to learn Informatica and, I have mentioned these steps by taking the thing in mind that you are a beginner:-
Before starting with Informatica you should have a working knowledge of SQL, especially functions, joins, sub-queries, etc. Knowledge of PL/SQL is also recommended.
Take up any Informatica Training Course and start learning this will not only give you a knowledge of Informatica but you will also get an industry-recognized certificate that will further help you get a job.
To learn Informatica I would suggest you take up Intellipaat’s Informatica Training Course. This is the best training course out there. You can also watch the following Informatica video tutorial to learn it in less time.