Doctecq lets several family members share one mobile number — this is normal and intended, because families often use one phone.
Because of this, the software does not stop you from registering two people on the same number. So the safe habit is simple:
Always search for the patient first — by name, phone, or file number — using the search box at the top. If they already exist, open them instead of registering again. This prevents duplicate files.
There is no automatic "merge" for duplicates, so searching first is the best way to keep records clean.