OnInitialize - access form controls in D365

go to Form- Events - OnInitialize - copy event handler

[FormEventHandler(formStr(ProjTableCreate), FormEventType::Initialized)]
    public static void ProjTableCreate_OnInitialized(xFormRun sender, FormEventArgs e)
    {
        MenuItemName        menuItemName    =   sender.args().menuItemName();

        if(menuItemName ==  "ProjTableCreateSubproject")
        {
            sender.design().controlName('ProjTable_INTC_Code').visible(false);
        }
        else
        {
            sender.design().controlName('ProjTable_INTC_Code').visible(true);
        }
    }