Software (engine) for searching through multiple .pdf.

Hello,

Do you know any good software for Win10 (preferably freeware but it’s not a condition) that would be best for quick searching through multiple .pdf files (loading all files at the same time – most likely at the beginning and then search them all) based on given keywords?

The output should be how many keywords does every file contain and also how many words in general does the .pdf files have.

Thanks!