I need to change the creation and modification date of an Illustrator file, I've tried with some applications but when I enter Illustrator >>>>>File Info, the change doesn't happen.
It is really urgent and I would like to know how I can do it.
First you need to figure out what tags you need to change. FAQ #3 (https://exiftool.org/faq.html#Q3) would normally be the starting point, but since you specifically want to figure out a timestamp, that can be narrowed down with this command
exiftool -time:all -G1 -a -s file.ai
Look at the output from that command and find which tags have the date you want to change. Then all you need to run is
exiftool -TAG="2021:05:24 12:00:00" file.ai
replacing TAG with the name of the tag you want to replace and setting the time to the new timestamp. See FAQ #5 (https://exiftool.org/faq.html#Q5) for more details on time related tags.