While there are libraries to help with the forgotten password flow, they require set up from the start. They need to be used for authentication before being able to use them for forgotten password.
If you set up your own auth plug, or used a different library that doesn't offer forgotten password, you may need to make your own controller/flow for forgotten passwords.
Layout how to make your own ForgottenPasswordController.
While there are libraries to help with the forgotten password flow, they require set up from the start. They need to be used for authentication before being able to use them for forgotten password.
If you set up your own auth plug, or used a different library that doesn't offer forgotten password, you may need to make your own controller/flow for forgotten passwords.
Layout how to make your own ForgottenPasswordController.