My Macboo pro from 2013 wont update past El Capitan

PS: "Software Update" won't be there in El Capitan 10.11.6.

You may look (and find one that doesn't do much) in

"About this Mac" under the  icon menu in Finder.

It may be the first item to appear in small box menu.

To find hints and try to download a newer installer, that

then should attempt to get an Installer, to download it;

you'd use the "How to get old versions of macOS" link.

A second page that may/or not help get the same link..

..would be same file-name, & directly downloadable:

The article's name may throw you, and perhaps that item

may never be used; however if you bookmark these things

create a new category in browser for 'apple macOS', etc.

• How to create a bootable installer for macOS - Apple Support

https://support.apple.com/en-us/HT201372

[Each system version name in the above, has direct link file D/L.]

..PSS: adobe Flash player does nothing & should be uninstalled..

Good luck!🌞☃️

Good afternoon DarthBalls78,

Welcome to the Apple Support Communities!

It sounds like you are trying to update your 2013 MacBook Pro, and we'd like to help.

It appears you have reviewed the Update macOS on Mac article.

What do you see when you click on the Software Update button in System Preferences? Do you see the option to upgrade to macOS Sierra? What happens when you try?

How to get old versions of macOS

If the issue persists, please reply to this thread and we'll do our best to help you!

Take care.