We can set credit limit for customer. Customer can purchase product or services up to certain limit. Even D365 for finance and operations provide us option to generate error message and stop processing of Sale order or just show error message and let the transaction happened.
For this you have to enable customer credit limit option from Account Receivable => step up => Account Receivable parameters.
In Account receivable parameter form, you can found Credit limit option in Credit Rating menu
If you explore Credit limit type you find following options
On selecting None, which is default means, credit limit functionality is disabled. Balance means, credit limit check against
Customer current balance, Next option is balance plus amount generated against packing slip and Product Receipt.
Third option is Balance + all include Packing slip, sale order and transaction activities.
Next option is when message exceeding the limit
We find one more option is on this page. This option is either apply credit limit on free text Invoice on .
Now we can set credit limit on Customer page, For this open required Customer and form detail page you can update credit limit. You can find Credit limit in Credit and collections fast tab
For more detail explore following link: