Automating the lead/opportunity generation will considerably improve your efficiency. By default, any email sent to sales@database_domain.ext will create an opportunity in the pipeline of the default sales channel.
Configure email aliases
Each sales channel can have its own email alias, to generate leads/opportunities automatically assigned to it. It is useful if you manage several sales teams with specific business processes. You will find the configuration of sales channels under Configuration ‣ Sales Channels.
