How do you stop your kids from biting their fingernails?

Keep calling his attention every time you'd see your child doing it. I don't know how long you'll be doing it but I guess it will help. Eventually, you should see some improvement. Just be consistent in reminding your child.

Remove from his mouth or distract his attention away from his fingers ... grab his hands and walk to another place to show him something to divert attention

Remove his hands every time you would see him do it. Never ever stop until you see your child not doing it anymore.

Just keep on removing his fingers from his mouth. Nakaka pagod pero it one of the effective ways.

Cut then short regularly and this may help to prevent them from biting.

always prereminder her whenever she try to bite her fingermrnails..

Cut them short regularly. They bite because they're still long.

Keep the nails short. Keep fingers busy with a fidget cube.

just tell them its not right to do that..

Regularly cut it short.