The mammoth already has a platform saddle in ark mobile but you have to buy the engram with real money. Click the up arrow if you want to help convince wildcard to add it into all versions of ark fully including ark mobile for free!!! Help start the petition revolution!!!!
If you see one near a body of water get a aquatic animal and start shooting it with tranq arrows/darts while your in the water stay away from the land or the mammoth will try to attack you if your not on land then it won’t noticeonce it’s knocked feed it
If taming, its easiest to either tame on outskirts like everyone else said or take a fast, leveled up dino with you for protection. I used my rex I tamed right before it and I had my argentavis to take him home. They keep up rather well unless you're going through a jungle. Shoot it in its trunk for easiest ko (I used darts. On a low level mammoth it can take 2 darts with the rifle to take em down easily)