Is P4O10 ionic or compound

You misunderstand between 'IONIC' and 'COMPOUND'.

All substances , except elements, are COMPOUNDS. Compounds may then be divided into three types of bonding, they are IONIC, COVALENT and METALLIC.

P4O10 (Phosphorus Pentoxide) is a COMPOUND. However, it is bonded COVALENTLY, by electrons sharing with adjacent atoms. (A bit like linking arms).

To compare

NaCl ( Sodium Chloride) is a COMPOUND. However, it is bonded IONICALLY. By electrons being lost or gained to form ions. Oppositely charged ions come together by Electrostatic Attraction, a bit like the N & S Poles of a magnet.