Create login and user for MSSQL Server database

1. Check the login present in the Microsoft SQL Server

USE MASTER
GO
select sp.name as login,sp.type_desc as login_type,sl.password_hash,
       sp.create_date,sp.modify_date,
       case when sp.is_disabled = 1 then 'Disabled'
            else 'Enabled' end as status
from sys.server_principals sp
left join sys.sql_logins sl
          on sp.principal_id = sl.principal_id
where sp.type not in ('G', 'R')
order by sp.name;
GO

2. Create a login for SQL Server:

-- create the user on the master database
USE [master] 
GO
CREATE LOGIN [LoginName] WITH PASSWORD=N'MyPassword'
Go

3. Check the user present for the database you want to create permission or access.

USE [DatabaseName]
GO
select name as username,
       create_date,
       modify_date,
       type_desc as type,
       authentication_type_desc as authentication_type
from sys.database_principals
where type not in ('A', 'G', 'R', 'X')
      and sid is not null
      and name != 'guest'
order by username;
GO

4. Create the user for a particular database and assign privilege DB owner:

USE [DatabaseName]
GO
CREATE USER [UserName] FOR LOGIN [LoginName]
Go

-- Assign DBOWNER Priviliges to username
USE [MyDatabaseName]
GO
ALTER ROLE [db_owner] ADD MEMBER [UserName]
GO