How to invoice an LLC?

Question

Law in IT

For a long time I worked according to the scheme:
I named the price - I took an advance payment - I did most of the work - I took the remaining payment - I completed the work
Now I have to open a legal entity. person, and several questions at once:
1) How to properly issue invoices before work when working with an LLC. Is it possible to issue a full invoice for all the work at once, or is it possible to issue 1 invoice for prepayment, and at the end of the work another invoice for the balance? How is it done correctly? I heard that LLCs like to pay on certain days, so it may be inconvenient for them to receive several invoices? How are you doing?
2) If you open a self-employed person, then the current account, it seems, does not open? Or opens? And as far as I understand, it will be necessary to open a regular debit card at the bank and report that it receives receipts from which tax must be removed. In this case, shall I only provide the card number to LLC?
Sorry if the questions are stupid, but it's really important for me, as a beginner to work in white, to know how it all happens in general. And then on the Internet it is not clear, for example, "through the application of my tax, you can send details for payment." It is not clear what these details will look like? And where will the money be kept? Etc.

Answer 1

Now you have to open a legal entity,

Do you want to open an LLC and bill another LLC? or:
1) You are talking about IP.
on the issue - in some LLCs, indeed, they can pay on certain days. Please clarify right away. And even better, indicate in the contract the dates of payments and penalties for late payment. Then these days will be "certain". The number of accounts is not limited.
2) about the self-employed. There is no obligation to open an account. But the organization is unlikely to pay in cash. Check with them.
Settlement account - go to any bank, they will tell you everything. And if you open an account, they will print the details on a piece of paper.
not a card, but an account. Provide details to the LLC. It will be necessary to indicate in the contract that you are self-employed.
The LLC does not withhold taxes from the self-employed. The tax office will issue

Answer 2

I know that this question is no longer relevant, but it may be useful in the future.
1. Invoices are issued in accordance with the terms of the contractual relationship.
1.1. If the contract contains a prepayment condition, then the invoice is usually issued for the amount of the prepayment, and then for the balance, which must also be specified in the contract.
1.2. Stated in 1.1. does not mean that you cannot invoice the full amount. Just normal accountants will not transfer everything at once to you, but only the amount of the prepayment.
1.3.

OOO like to pay on certain days

- refers to those who have normal (professional lawyers, financiers and managers), because budgeted for a specific period. And this doesn't just apply to LLCs.
2. Self-employed - this is generally narrow, because. limited to specific specialties.
2.1. Not a single legal entity will work with the self-employed. (See item 2) It is easier for them to hire an employee, and this is connected not only with taxes.