Welcome to Android Central! First, make sure you install another keyboard app (like Gboard) from the Play Store and set that as your default. Then go to Settings>Apps, and look for Touchpal Keyboard. If you see an Uninstall button, then tap it. If you only see a Disable button, then it's a preinstalled app that the phone won't let you get rid of -- but you can still Disable it, which means it will be prevented from opening, and also will be prevented from updating through the Play Store.
If there are a bunch of Touchpal Language packs preinstalled, you could probably uninstall those. But there might be a lot of them to uninstall. The Lenovo Tab 4 8 that I got for my daughter came with Touchpal, and there were something like 50 preinstalled language packs. They could all be uninstalled, but it was a tedious process.
Touchpal Keyboard has been associated with some pretty sneaky stuff (like adware), so I definitely agree with getting rid of it. It was kind of appalling when I heard that HTC started using it as their stock keyboard (kind of like Clean Master showing up on Samsung and ASUS phones).