invitations

ok so my invitations are in production and so i want to be prepared

now does it matter what type of pen i get?

also to close the envelope with the momogram what should i do..i dont think i want to glue it closed it may ruin the invitation but i will glue the top part onto it but how do i do the bottom...also what do i buy as far as glue and stuff

TIA

thats it im getting ready im mailing them out next month...crazyyyyyyyyy