Hi Harshita,
You have create custom login page.
follow the below link.
https://academy.mendix.com/link/modules/183/lectures/1419/3.4-Custom-Login-Page
Hi Harshita,
You can create a layout by right clicking your module name-add other-Layout and create a name such as Atlas_Login. Create a page using login form login layout . Remove the data view and add a validation message,( in toolbox) username and password. Please follow the image for validation message. Hope it helps!!!