OS Help Needed - Mac OS Sierra to Catalina

[Redgun71]

I've decided to upgrade my MacBook Air 2017 (2.2 GHz Intel core i7), so I clicked on the icon already on my Mac - "Install macOS High Siera" and a message pops up "This copy of the Install macOS High Sierra application is damaged, and can‘t be used to install macOS.
So then I try another icon "Install macOS Mojave" and the same message pops up "This copy of the Install macOS High Sierra application is damaged, and can‘t be used to install macOS.
I go to the App store and cannot find either of these 2 OS, also I click on Updates and got a reply of "No updates available".

1) Can I upgrade from Sierra 10.12.6 to Catalina?
2) Should I upgrade to Catalina?
3) Will Catalina work with the others apps/software that I have like various Adobe CS6 products and MS Office 2016 (currently having update problems maybe due to Sierra)?
4) Can I delete the install files (High Sierra & Mojave) on my Mac?

Thanks

 

[Grimeire]

1) Can I upgrade from Sierra 10.12.6 to Catalina?
Yes you can
2) Should I upgrade to Catalina?
Catalina only allows apps signed by Apple so some apps will no longer work if you update.
3) Will Catalina work with the others apps/software that I have like various Adobe CS6 products and MS Office 2016 (currently having update problems maybe due to Sierra)?
see point 2
4) Can I delete the install files (High Sierra & Mojave) on my Mac?
Yes, right click delete/move to trash and then you many have to enter your password. Then empty trash

 

[Redgun71]

Thank you Grimeire, I've just scrolled down on the App page and saw compatibility OS X 10.9 or later.