Always suddenly shut down Adobe Acrobat Reader when I try to paste things as comments. I can't do anything. so frustrated

There are a few reasons why Acrobat may crash. 

It could be a corrupted file. Have you tried updating Acrobat Reader?
You can fine this from Acrobat, selecting Menu > Help > Check for updates

You could try remove Acrobat completely and reinstalling.

There could be Protected view conflicts
To turn off protected view:
1. Open Acrobat.
2. Go to Edit > Preferences > Security (Enhanced).
3. Uncheck Enable Protected View.
4. Restart Acrobat.

More information on the above can be found at:​​​​
https://helpx.adobe.com/acrobat/desktop/troubleshoot/performance-issues/acrobat-crashes.html

Post how things go, what you have tried and the results.