From the Contacts tab, tap the appropriate contact.
Tap Edit contact (located at the top).
Enter/edit any of following information then tap Save (located in the lower right): To change the account type, tap the Dropdown menu located at the top then tap the desired account (e.g., SIM, Google, etc.). Available options may vary.
Phone To add a pause (a 2-second delay between numbers) or wait, tap then tap P or W as appropriate.