What over the counter deworming/defleaing are the most effective?

i just got a chihuahua pup 3 days ago he was born april 11th, so hes about 10 weeks old and i am wanting to deflea and deworm him but am wondering what is best to use and what age i can do this. i give him my shots myself. also what regular shampoo is best to bathe him in. thanks!!