PlayFabSettings.staticSettings.TitleId = ""; // Change this value to your own titleId from PlayFab Game Manager
PlayFabSettings.staticSettings.DeveloperSecretKey = ""; // Change this to your title's secret key from Game Manager

public static async Task<PlayFabAuthenticationContext> LoginAsTitleEntity()
{
    GetEntityTokenRequest request = new GetEntityTokenRequest()
    {
        Entity = new PlayFab.AuthenticationModels.EntityKey()
        {
            Id = PlayFabSettings.staticSettings.TitleId,
            Type = "title",
        },                
    };

    PlayFabResult<GetEntityTokenResponse> entityTokenResult = await PlayFabAuthenticationAPI.GetEntityTokenAsync(request);

    PlayFabAuthenticationContext authContext = new PlayFabAuthenticationContext
    {
        EntityToken = entityTokenResult.Result.EntityToken
    };
    
    return authContext;
}

private static async Task<PlayFabAuthenticationContext> LoginAsPlayer(string customId = "GettingStartedGuide")
{
    LoginWithCustomIDRequest request = new LoginWithCustomIDRequest { CustomId = customId, CreateAccount = true };

    PlayFabResult<LoginResult> loginResult = await PlayFabClientAPI.LoginWithCustomIDAsync(request);

    return loginResult.Result.AuthenticationContext;
}

private static async Task UpdateEntityDisplayName(PlayFabAuthenticationContext context, string customId)
{
    SetDisplayNameRequest request = new SetDisplayNameRequest()
    {
        AuthenticationContext = context,
        DisplayName = customId,
        Entity = new PlayFab.ProfilesModels.EntityKey()
        {
            Id = context.EntityId,
            Type = context.EntityType,
        },
    };

    PlayFabResult<SetDisplayNameResponse> updateNameResult = await PlayFabProfilesAPI.SetDisplayNameAsync(request);
}