Your options are:
- Put them all on one phase (while respecting any DNSP limits ).
- Spread them out over 2 or 3 phases. If you have 3 phases to play with you can install 3x the capacity compared to a single phase supply and not upset your DNSP.
If you have a 3 phase supply you should get a 3 phase net-meter when your solar is installed. This meter will ensure that you are not disadvantaged financially by having micro inverters on a 3 phase supply as described here: