Hi there and welcome
You can replace it yourself if you are technically a bit capable and can dismantle the printer.
The unit you can purchase from here
CLICK ME TO OPEN
The Fuser unit is to the back of the printer where the paper comes out, so you would need to remove the cover
But in my experience, with the cost or printers these days and the good possibility due to the age / use of the printer, it is better to purchase a replacement as the long term costs generally outweigh fixing it yourself.