database design: what fields are must for a user table in database?

I am trying to design a user table for MySQL.

for now, my user table looks like this

users (
BIGINT id,
VARCHAR(?) username,
VARCHAR(?) password,
VARCHAR(254) email,
DATETIME last_login,
DATETIME data_created
)

what other fields should I also include and why do I need them?

what fields should I exclude from above and why?

how many characters should I allocate for username and password, and why?

should I use BIGINT for id?

Thank you in advance for your helps.

ADDED I am going to use the table for social web site, so 'users' mean people around the world.