Im on an older mac running Mavericks 10.9.5. Can I update to newest iOS?

Click on the  top left of your screen and select About This Mac, that will tell you the year of your Mac.

If it is a 2013 then it can upgrade to macOS Catalina, but this will definitely not run your Adobe Creative Suite.

Catalina does not run 32bit apps, although Adobe Creative Suite is 64bit there are 32bit elements, so its functionality

will be compromised. You need to find out which version of macOS can run your Adobe Creative Suite without issue.

Use this app, https://roaringapps.com/apps enter Adobe CS and the number version you have into the Search field

the results will allow you to make a decision as to what OS might best suit your needs.

How to upgrade to OS X El Capitan – Apple Support

How to upgrade to macOS High Sierra - Apple Support

How to upgrade to macOS Mojave - Apple Support

Before upgrading make a full back up of your Mac.

Check that third party apps you use have updates available for the new OS.

Check that your printers/ scanners etc have updated drivers and software available for the new OS.

If you are considering upgrading to Catalina.

Your Mac is probably running 32bit apps and these will need to be updated to 64bit apps,

some updates may be free, some may be paid. Use this app to discover which apps you have

are 32bit, https://www.stclairsoft.com/Go64/. Once the list has been created you can then

contact the developers of the apps to see if they provide 64bit updates. 

How to upgrade to macOS Catalina – Apple Support

That depends on the specs of your Mac, especially model and year of manufacture. You can find that by going to Finder menu > About this Mac. Please post the specs, everything except your serial number.

Don't upgrade. Might seem appealing but there is planned obsolesce "bugs" that will slowly cause performance issues with your older device. You'll be troubleshooting all kinds of issues that will eventually have support sending you into the apple store just to be up sold a newer device. Both my 2011 Mac and 2013 Macbook Pro have all kinds of performance bugs, including random disconnects of the internet, bluetooth and random resets. I spent months and months troubleshooting this with support including taking it into the store only to be told I shouldn't have such a new iOS for the iMac and was proceeded to be upsold a new machine. Classic planned obsolece sales model from apple. Slowly lag performance that eventually bricks customers devices and machines only to drive them into th store to be upsold.

Your experience is not the norm. The OP here is having issues with his browsers precisely because they are no longer supported. Upgrading is the proper route to take. In fact it is usually advisable to upgrade as long as your Mac meets the specs and there are no must have applications that won't run on the upgraded system. Upgrades/updates contain important security updates and also new features.

By apple support own admission my iMac 2011 was rendered useless because it couldn't handle the iOS on it, this was apple approved as an appropriate upgrade. No major issues with the machine prior, but forced update after forced update (hint planned obsoleteness) and in the end the machine now requires about 4 or 5 resets a day and now can't stay connected to the internet. After months and months of troubleshooting I eventually had to take this into the apple store and they promptly said I should get a new machine "really it's just an old machine"... I literally only use it for a web browser, nothing stored on it, no apps or software on it and it can't even just run a web browser???

Classic apple upsell planned obsoleteness sales model.... slowly brick em, drive them in, and watch the genius bar bill em.

This is the 2011 iMac that apple bricked, I have other machines with very similar outcomes.

Yes, I saw your other post. I'm running a mid-2010 myself fully upgraded to High Sierra and never have any issues with it. Not browers, not Bluetooth, not slowness or anything else. You don't need a new machine, you need to troubleshoot the issues.

On the other hand, I'm very prepared for the fact that anything can wrong with Mac at any time and I'll probably need to replace it soon. 10 or 11 years is very long time in computers. Also, as far as I know Apple Stores will not work on a Mac of our vintage, they don't store the parts that long.