Action name: OpAnyOffsetThis command converts the immediate operand of the current instruction/data to an offset from any segment.
IDA will ask to choose a base segment for the offset.
If a range is selected using the anchor, IDA will perform 'en masse' conversion. It will convert immediate operands of all instructions in the selected range to offsets. However, IDA will ask you first the lower and upper limits of immediate operand value. If the operand value is >= lower limit and <= upper limit then the operand will be converted to offset, otherwise it will be left unmodified.
If the cursor is on the first operand (the cursor is before ',') then the first operand will be affected; otherwise, all other operands will be affected.
To create offsets to structure members use Convert to struct offset command.
offset by data segment/no offset by current segment Edit|Operand types|Offset submenu. Enter #th operand manually commands. Set operand type