Can i shere paid commissions from fiverr.com on here. i used to post on zerochan.net but a mod deleted my images so im wondering if i can post them here.

You can share your own Anime themed works here. Just source the image via putting the parent link to it.
Or if you own it, why not name it.

How do I contact ppl for commissions on here?

You need to take permission to the commissioner first before posting it.

If you wish to contact an artist for a commission, you will have to discover what platform they are using (twitter, pixiv, etc.) and message them there. Most images on Safebooru have a source link on them that you can use to locate the artist.