MODIFY and MODIFYALL in D365 BC:
(1) Introduction: When records are modified in the tables via “AL” then MODIFY method is used. Note: recommended to modify any record in the table, specify filters on that record using “GET” or “SETRANGE” & “SETFILTER” for getting the records which you want to modify.
(2) Syntax: Modify.
[Ok :=] Record.Modify([RunTrigger]) |
(3) In the below example, Bill-to Address information is changed in the sales order, using MODIFY & MODIFY(TRUE) method as shown.

(4) Introduction: If you modify a set of records in one go, then the MODIFYALL method is used.
(5) Syntax: MODIFYALL.
Record.ModifyAll(Field, NewValue [, RunTrigger]) |

(6) There is another way to modify a set of records in one go by using the “MODIFY” method with REPEAT UNTIL loop as shown.

Use of SETRANGE and SETFILTER in Dynamics 365 Use of FINDFIRST FINDLAST and FINDSET in BC D365 Creation and Usage of FilterPageBuilder in BC D365 Page Extension Object– Microsoft Docs |