The Japanese verb motsu (持つ) means to hold. This verb is used to show that you are holding something or you have something. Motsu can only be used to express things you possess that are inanimate.
(I) dont have anything = nani mo mottenai (何も持ってない)
Do you have key? = kagi o motte imasu ka (鍵を持っていますか)
Do you have pen? = pen motte iru? (ペン持っている？)
Hold this = kore o motte (これを持って)
If you want to speak about animals that you own you use the verb kau (飼う). This verb means to raise.
(I) am raising horse and cow = uma to ushi o katte imasu
Do you have a cat = neko o katte iru no (猫を飼っているの)
(I) don't have cat = neko o katte inai (猫を飼っていない)
You are probably wondering what you would use if you want to talk about people. It would be rude to say you possess someone so instead you use the verb iru.
(I) have a girlfriend = kanojo wa imasu (カノジョはいます)
(I) have a friend = tomodachi wa iru (友達はいる)