Make sute you have installed .NET EF tools
dotnet tool install --global dotnet-efRun dotnet ef migrations add <MigrationName> in Blazor server application project directory, with --project parameter indicating project with database context and migrations
Eg:
cd .\TaxAssistant.JPK\Server\
dotnet ef migrations add InitialDatabase --project ..\..\TaxAssistant.JPK.Database\TaxAssistant.JPK.Database.csproj --context DatabaseContextOr:
dotnet ef migrations add JPK_EWP --project TaxAssistant.JPK.Database --startup-project TaxAssistant.JPK/Server