Two last names without a hyphen?

SaaSha • 26 | 🇨🇻 + 🇧🇲

Does anyone know the process of legally having two last names without a hyphen? I know it’s a thing but how does it work on paperwork and doing the name change legally? Do you just fill in the last name field with two last names including the space? Anyone have two last names without a hyphen? Have you ran into any issues with paperwork