Canonical is set to pull the plug on Ubuntu 19.10 ‘Eoan Ermine’ some time this month. If previous release cycles are anything to go by, support could end anywhere between mid- to late-July so that gives you about a week to get ready to upgrade. If you do not upgrade, your system will not receive any new updates which could leave it open to exploitation.
Canonical, helpfully, has put together a simple guide which will help you move from Ubuntu 19.10 to the recently released Ubuntu 20.04, while Ubuntu upgrades tend to be safe, be sure to heed the warning at the start of the tutorial about backing up your files as things could mess up, although it’s unlikely.
If you’d prefer to do a clean installation of Ubuntu or another Linux distribution, you can download the relevant ISO, write it to a USB and perform a clean install. Again, you’ll need to back up the data you want to keep because a clean installation will erase the hard drive. It is, however, recommended if you’ve messed up your current install or just want the vanilla Ubuntu 20.04 experience without any residue from Ubuntu 19.10.
Once you jump to the latest version of Ubuntu, you will benefit from a new version of GNOME, a newer Linux kernel and other updated packages. The latest version of Ubuntu will receive updates for the next five years until April 2025.