How to show date and time user's timezone wise

suppose i have a interface from where insert data to database. database is running in USA pc. user may enter data from USA,UK,Germany and India. so their timezone is different.

so do i need to store date and time as utc format ?

how to send timezone info of user to sql server store procedure and in sql server store procedure convert utc date and time to supplied timezone wise date and time ?

how to capture user timezone id or name which i will use to convert utc date and time to specific user time timezone info ?

i need to develop a application which show data entered by user from different country and data will be stored in USA pc.

please guide me detail.