Unless the datasheet of the component explicitly requires, go for NSMD (non-soldermask-defined) padstacks, see chapter 1.3. This means the solder mask opening shall be slightly larger than the copper pad. Normally the shape is the same and the gap should be between 0 and 0.1mm (according to IPC). Some PCB fabs, like jlcpcb, have their own minimum gap (0.038mm as of early 2025). This is probably to compensate for mask placement tolerance (so that a slightly misplaced mask does not reduce copper pad exposure).
Recommended gap size is 0.075mm; if the footprint is designed for the 'C' density level, recommended gap size is 0.045mm.
If there is a row of pads, e.g. in case of SOIC or TQFP, each padstack shall have its own mask shape. With reasonable pitches there will be enough mask left in between pads to meet PCB fab minimal requirements (0.1mm at jlcpcb in early 2025). However if the mask bridge between pads is too small because of the pitch being too small, it is better to remove mask from over the whole row. This can be done in two ways:
The two methods shall not be mixed.