Presuming you need to record all your transaction with every single detail, including your customer data, and you want to make the sell menu requires Customer Information, you can set it to default, so the transaction can not be made without customer information. You can try this following method:
I. Set the default setting
Step 1. Go to Setup menu, click more setting, and select module
Step 2. Go to the Sell section and tick YES in Customer Required form, then Save
II. Sell Menu
*Important Note: After the save was made, you are not longer allowed to use Sell menu without inputting the Customer Information.
You might also like to read this article:
If your store policy has a Salesperson in every transaction, you can provide a Sales Person Required configuration for each sales transaction. Sales Person Required in Sell Menu.
To prevent sales that exceed capacity/stock, we have a config that can help. Please check the following article:Configuration to prevent overselling in DealPOS App.
You could also hide your Price with Price Visible Restriction.