We use apnaa and its forms in the place of possessive forms of pronouns in the possessive phrase. We do this when the subject of a sentence/clause and the possessor in a possessive phrase is the same person.
We use apnaa अपना if the next noun is masculine and singular.
We use apne अपने if the next noun is masculine and plural. We can also use this if the next noun is masculine and singular too when you want to pay respect to the person.
We also use apne अपने if the next noun is masculine and is followed by a case sign.
We use apnee अपनी if the next noun is feminine and singular/plural.
Examples:
I am eating my apple – मैं अपना सेब खा रहा हूँ – main apana seb kha raha hoon – Here apple is masculine and singular and so apnaa is used before it.
I am eating my cherry – मैं अपनी चेरी खा रहा हूँ – main apanee cheree kha raha hoon – Here cherry is feminine and singular and so apnee is used before it.
I am bringing my father to school – मैं अपने पिता को स्कूल ला रहा हूँ – main apane pita ko skool la raha hoon – Here apne is used before father as a way for respecting him.
I am selling my houses – मैं अपने घर बेच रहा हूँ – main apane ghar bech raha hoon – here apne is used as houses is masculine and plural.
My mother sleeps in her room – मेरी माँ अपने कमरे में सोती है – meree maan apane kamare mein sotee hai – here room (कमरा) is masculine and singular but a case sign (mein) follows the room and so we have used apne before room.
I went with my father to shop – मैं अपने पिता के साथ खरीदारी करने गया – main apane pita ke saath khareedaaree karane gaya