Witness signature required for leases?

[Joe R.]

Is a witness signature field required at the end of each tenant lease?

This blank field is currently next to the Tenant signature and the landlord signature fields on a lease document I am customizing.

If witness signature field is required, who qualifies as a witness? 

anyone? or does it have to be a notary?

Can I witness the Tenant sign and the tenant witness me sign?