This post shows you how to fix 'DbContextOptionsBuilder' does not contain a definition for 'UseSqlServer' and no accessible extension method 'UseSqlServer'.
Error
Severity Code Description Project File Line Suppression State
Error CS1061 'DbContextOptionsBuilder' does not contain a definition for 'UseSqlServer' and no accessible extension method 'UseSqlServer' accepting a first argument of type 'DbContextOptionsBuilder' could be found (are you missing a using directive or an assembly reference?)
To solve the problem you can right click on your project, then select Manage Nuget Packages, finally install it.
PM > Install-Package Microsoft.EntityFrameworkCore.SqlServer
to your ASP.Net Core project,