Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
What version of Mac OS X are you using now ? Click on the Apple icon and select About This Mac
Hi there, Sorry for the delay. Had to go offline since it was very late in here. It is completely option and you only need to accept if you have any difficulty upgrading it yourself.
To get the latest version of Mac OS X (if your Mac is compatible), open App Store application from Applications folder and you will fine Mac OS X 10.11 El Capitan there. Click Get button and it will be downloaded. You can see the Download progress by clicking the Purchases tab at top. After downloading it, you will be asked to update automatically. Just follow the onscreen instructions to update.
You can also download El Capitan from here (this link will take you to App Store) --> https://itunes.apple.com/in/app/os-x-el-capitan/id1018109117?mt=12
If you are having difficulty with Safari, then you can try other browser like Google Chrome which is much better than Safari. Download it from here --> https://www.google.com/chrome/browser/desktop/
Let me know how it goes please.