Need help with my Tarantula

Do they need water dish just like scorpions?
If they need one, should i use sponge/cotton or water dish?
thanks.... she is still 2cm by the way

There's not really a need for water dish for any tarantula which are less then 3 inch legspan.
Weekly mist at the side of the enclosure's wall would be ideal, try to maintain 1/3 of the substrate surface slightly moist at all times.

For your second question,
No, not advisable to use sponge/cotton as they might be great breeding ground for bacteria.
A simple shallow water dish with pebbles would suffice.

A recent thread for your reading:
https://scorpionforum.darkbb.com/t8955-new-baby-spider-help

By the way, what species is your tarantula?

thanks sir! i got b. auratum....is this the red leg or the red knee? i dont really know the difference

Go with the scientific name, it's more accurate.

Brachypelma auratum's common name is Mexican Flame knee.
Brachypelma emilia's common name is Mexican Redleg.

They can be kept in the same way, try to search for their individual caresheet/ google image search for their differences in outlook.