[brk]

As other commenters have mentioned, you're not going to be able to insert your own clauses into any standard employment agreement.

However, every large employer has already relocated hundreds, if not thousands, of employees. They have similar clauses that are approved, but as a candidate you may need to ask to have such a clause included.

Depending on the hiring market, the specific position, and your unique circumstances, you may or may not be able to get something added to the agreement, but it would rarely be unjustified to ask for some kind of relocation protection.