You can send documents by e-mail.
For using e-mail sending on your Bitrix24 you should be set up "E-mail integration" (/crm/configs/sendsave/).
When using the method for sending e-mail by Save&Send technology the mail will be associated with CRM entity. A letter will be sent from the common e-mail of CRM.
When using the method of sending e-mail by Activity Stream the mail will not be associated with CRM entity. A letter will be sent from the personal Bitrix24 address of employee.