how to change the default positioning of modal in bootstrap?

Answer 1

If you need to change the bottom position of the modal, you need to modify the max-height of the modal-body:

.modal-body {
  max-height: 75vh;
}

As other answers have said, you can adjust the right and top on the modal-dialog :

.modal-dialog {
  top: 10vh;
  right: 5vw;
}

• "vh" means "% of view height"
• "vw" means "% of view width"