It's not clear why you are asking about "how to do the 1099." You don't issue a 1099 to yourselves. If a client is a business, not an individual, and pays you $600 or more in a year, the client has to issue a 1099-NEC to you.
If you operate your business as a qualified joint venture, you each file a separate Schedule C showing your individual shares of the business income and expenses. You divide all income and expenses between you according to your respective percentages of ownership. If you do get a 1099-NEC from a client that is a business, it doesn't matter which one of you the 1099-NEC is issued to. You split the income based on your percentages of ownership. You do not need to have the client issue separate 1099-NEC forms to each of you.
A client who is an individual does not issue a 1099. You each just report your individual shares of the income on your individual Schedule C.
