i have macOS Catalina 10.15.7 and i can't update safari

Mostly you just need a more modern Browser than Safari on Mojave, or High Sierra like Firefox or Brave.

https://brave.com/

https://www.mozilla.org/en-US/firefox/83.0/system-requirements/

Firefox 83.0 System Requirements (mozilla.org)

Opera…Thanks

https://www.opera.com/download/requirements

Opera system requirements | Opera

Thanks to A Brody, Browsers by Mac operating system…

Browsers by Mac operating system - Apple Community

First thing was that my Safari icon popped off my tool bar and is gone. I went to applications and brought it out again. It wont open. I get that big explanation box that says it didn't open. I did a disc utility to see if that would help. NO GO. I tried to download a new Safari. I waited and then tried to install it. NO GO. I went to the comp store where I bought it. The guy told me to try and refresh it. I can't seem to do it correctly. I came here and went through some steps. Now I'm told that by tomorrow I will be contacted to reset my password. I'VE GOT NO PROBLEMS WITH MY PASSWORD. I want Safari back.

To upgrade Safari from Safari 15.6.1 to a later version you would need to upgrade your Mac from macOS 10.15.7 to a later version.

If you can’t or don’t want to upgrade, you may want to use a 3rd party internet browser that supports running their current version on your Mac. One option is Chrome: https://www.google.com/chrome/

The model year of an iMac is available at Apple menu > About This Mac.

A late 2012 through late 2013 iMac can be upgraded to Catalina 10.15.7 but no later. See: How to download and install macOS - Apple Support

A mid 2014 and late 2014 iMac can be upgraded to the latest version of Big Sur macOS 11 but no later. See: How to download and install macOS - Apple Support

A late 2015 iMac can be upgraded to the latest version of Monterey macOS 12 but no later. See: How to download and install macOS - Apple Support

A 2017 iMac can be upgraded to the latest version of Ventura macOS 13 but no later. See: How to download and install macOS - Apple Support  

A 2019 or later iMac can be upgraded to the current version of Sonoma macOS 14. See:How to upgrade to macOS Sonoma - Apple Support