Hi, my name is Hernan from Peru. I deen any support about how can I return my ipad to an old IOS version because now it´s very slowly

You cannot. Apple does not support downgrading of iOS. There is no way to downgrade, or install an older iOS on the device. You need to troubleshoot the device to correct your issues. User Troubleshooting consists of Restart, Reset, Restore from backup, Restore to factory.

You're welcome.

Try resetting All Settings found in the Settings App under General and in the right column under Reset.
Try resetting histories and deleting/resetting caches in all of the web browsers you use.
If you use Safari, these functions maybe in the Settings App under Safari.
Other web browsers have their settings inside of the running app, itself.
If your iPad has been activated for iCloud, in the Settings App under iCloud, to the right, under iCloud Drive, tap iCloud Drive and make sure Safari is turned off for saving Safari data to iCloud Drive.
Also, under iCloud in the Settings App, in iCloud Drive, disable the saving feature for any other apps that you DO NOT want data being saved automatically to iCloud Drive.
If using Safari is still causing issues,
Try changing/using another, different third party web browser.
I don't use iOS Safari too much any longer because I found it causing me some headaches on certain websites I, regularly, visit.
I commonly use another third party web browser, Perfect Web Browser (there are others that may suit your web browsing style better, so look at all of them first to see which third party browser may work better for you) and I never experience a lot of the issues that Safari was causing.
In the Settings App under the General tab, to the right under Spotlight sesrch, try disabling the search under apps that really do not need a search, like some games, remotes, apps that really do not need to be searched, etc., to reduce the list for Spotlight to search.
Try turning on Reduced Motion.
This is found in the Settings App in the General tab the left panel.
In the right panel look under Accessibility, the look for Reduce Motion and turn this feature "On".
You should see an appreciable performance increase on all iPad 2, 3 and 4 models.
In the Settings App under the General Tab, in the right column, look for Background App Refresh and turn this setting to "off".
Try a reset of your iPad by holding down both the Home and sleep/wake buttons simultaneously until your iPad goes to black and restarts with Apple logo, then release the buttons.
Good Luck!