To change your password on your Google account at any time:
Step 1: Go to your profile picture (on the top right of the screen.
Figure 1 Go to My Account
Step 2: Then select My Account as above.
Step 3: Click on Sign-in and Security in the first box you see.
Figure 2 Go to My Account
Step 4: Scroll down the page until you see the password section on the right side of the page. Choose Password.
Figure 3 Go to My Account
Step 5: Login to your Google account with your current password when you are prompted.
Step 6: Type in your password in the first box and again in the second and then click on Choose Password.
Your password is now changed. Once this is done, any devices using your Google account (phone) will ask for the new password.