In the event that you have forgotten your Google password, you are not alone, this is a common mistake and Google has few simple techniques on how to retrieve your account. The trick is being able to access your recovery options like a recovery phone number or email address, or to a device where you have already signed in.
1. Visit Google Account Recovery Page:
The initial point is to reach the official Google Account Recovery site. In most cases, you can get it by following the sequence of trying to log in to your Google account (e.g., Gmail, YouTube, Google Drive) and clicking on the Forgot password? Link.
2. Enter email address or phone number:
Google will also lead you to fill in your email address or the phone number. Provide the information and click next.
3. Select a Verification Method:
This is when a recovery option comes in. Google will conveniently offer you some means to confirm that you are an authentic owner of the account. Typical ones are:

• Obtain a verification code on one of your recovery phones: in case you have a recovery phone with a phone number registered to your account, then Google may send a verification code to the phone number by SMS. Go to recovery page and then you need to enter the code.
•  Receive a verification code on a recovery email: Just like with the phone method, on having a recovery email, the Google can send a code to the inbox on this particular email. 
• Enter the responses to the security questions: In case you have set security questions, Google will possibly ask you to provide one or more of them.
• Confirm an on-phone/tablet prompt: Make sure you have a Google account on an Android phone or tablet, and Google can show an on-device prompt on your phone or tablet. And you will simply need to tap on the device and press: yes, to effect verification of your identity. It is usually a fast and convenient way, especially when you can access a signed-in device.

Another method/I lost my phone/I have not got access to this mail: In case there is no access to the major methods used in recovery, Google has alternative methods. This may entail:

• Presenting an older password you can remember: Google may want you to provide an older password you used in the account to create your identity.
• Answering questions about your account: Google could ask you some questions on when you opened the account, what services you consume or even some contents that you could have done recently, to ensure that it is really you.
• Waiting by Google to verify: When it comes to How do I reset my Google password if I forgot it?, then you need to understand that in particular cases, particularly in the event that you are not able to access any of the recovery options, Google may take a longer period to verify via the process which implies that Google will contact you after a number of days once it has substantially confirmed your identity.