Why can't I Flag as Pick my images?
Unfortunately, we cannot offer you the 'Flag as Pick' (P) rating in Select. This is because 'Flag as Pick' is not actually metadata and it can only be read by Lightroom and added or removed inside Lightroom. All third party apps have this same restriction.
Alternatives for 'Flag as Pick'
This will work in practically the same way as 'Flag as Pick'. You will be able to put a tick on the images you like so it's easy to select them and SHIP them into Lightroom – just click the tick box, or better yet, tap T.
Now you can select only images with ticks using the filters, then ship those images into your editing tool of choice.
Please note, tagging does not write to metadata and can only be read by Select.
Many photographers use a 1-star rating (1) to signify their picks, but you could really use any rating you like. Use 1,2,3,4,5,6,7,8,9,p to try the different ratings, and 0 to clear them. The advantage of this method is that star and color ratings write to metadata so they can be read by other programs.
After shipping into Lightroom
If you wanted to, it's easy to switch to Flag as Pick after you've shipped into Lightroom. Just select all the images you just shipped, and apply the 'Flag as Pick' rating then clear their current rating if you want to.