please tell if I need to set up trust policy while creating roles and policy for user

IAM policies can be set directly for IAM users.
However, as a best practice, do not set IAM policies directly for IAM users, but create an IAM group and tie IAM policies to that group.
After that, it is best practice to make the IAM user belong to an IAM group.

Also, when creating an IAM role, if you do not have a trust policy set up, you will probably get an error in the first place when creating the role.
https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_for-user.html