Use a duplicate check rule to check if the data doesn't already exist in D365 F&SCM.
Before you can set up a duplicate check rule, set up the duplicate check to be applied.
You can apply these types of duplicate checks:
Basic matching: Checks which combination of table fields has duplicate values. So, the combination of field values must be unique in the table.
Fuzzy matching: Checks for duplicates applying fuzzy logic. A fuzzy duplicate check compares values from several fields. Based on the comparison, a duplicate score is calculated. You can start a duplicate check rule of type 'fuzzy matching' only manually. Therefore, define from which forms you can start duplicate checks of type 'Fuzzy matching'.