Once again you fail to mention the make and model of your oven...
Yotube videos show how to test and change an element in an oven - not all ovens have their elements in the same place. Sometimes behind a cover plate. Sometimes more than one element.
In the UK there are online suppliers such as e-spares or buyspares - but be sure to tell them the make and model when you call.
Are you sure that you have the confidence and skills to fix your oven?
Good Luck..., March 2017