Sometimes there are multiple companies created (by one person) for various reasons, however the safest way to handle this is to create a new bank account for each entity.
If you decide to keep the same bank account, keep in mind that the IRS, for payroll purposes, is tracking all of this activity and this will flag your entity if it is using the same exact bank account as another entity’s. This means that you will NOT be able to submit payroll tax deposits from multiple companies using the same bank account, UNLESS, you complete the proper paperwork and literally mail to the IRS.
The proper paperwork I am referring to is called the “EFTPS Authorized Account Holder Verification Form”. You will have to print this form, take it to your bank, and have your bank fill this out AND notarize this form. Then you will have to mail this form back to the IRS within 3 weeks (from the date of the original IRS letter that submitted this request to you).
All of this is sounds feasible, however in my opinion, it is probably the most efficient to just simply open up another bank account (within the same financial institution if you wish) and proceed with all of the new company’s financial transactions from there (including any opening/beginning balance contributions).
I say all of this because I believe that each entity should always have their own accounts (credit card, lines of credit, banks, loans, etc) attached permanently and not mix up with another entity’s accounts, including anything personally related. This approach will prevent any potential future breaches of legal barriers.