Step 1: Login to your Gmail account and select Gear and in upper right corner click settings.
Step 2: Click the Account and Import tab and select Import mail and Contact button.
Step 3: Type your email address to your account which you are added, and then click Continue.
Step 4: For the other account type your password and click Continue.
Step 5: Which you like to import select that particular items and Add label to all imported mail is used to share items to your Gmail’s account, Finally select Start import when it is ready.
Step 6: The process will start import, Once its completed click OK, And note that it will take two days to display.
Step 7: Suppose you like to delete the account from Gmail, go back to your Account and Import tab click delete option which is next your account. Now you have successfully transferred your account to Gmail.