How to see what changed in a file

I want to see what changed in /var/www/html. How would I do that? I have auditbeat running and have the file_integrity module on and have /var/www/html in the paths. Thanks

To see what changed in a file - you can actually diff the file - which shows the difference between the files. You can use online tools like diffchecker too. But more than that I don't know how to explain further - can you please elaborate further more- screenshots, log files, versions, steps...all would help.

Thanks
Rashmi