Hi there, brucec1.
I'm glad to help you set up invoices so you can keep bank transfers enabled by default. What you'll want to do is modify the invoice template and un-check the payment method so your customers can only use bank transfers when they pay their invoices. You'll be able to save these modifications as well so they'll be default. Here's How:
I'm also going to include a couple helpful articles for you, if you need future reference.
If you have any other questions or concerns, feel free to post them here. Thanks for joining the Community and have a nice evening.