When working with Gmail, you often need to add attachments to the messages such as the document, the picture or another email, etc. Please see below for details:
Step 1: To compose an email first by clicking the "Compose" button on the top left corner;
Step 2: Finish the "To" box and the "Subject" box, then finish the email;
Step 3: Click the "Attach files" icon at the bottom;
Step 4: Browse to the attachment file folder, select the file and click the "Open" button;
Step 5: You will see the attachments are now at the bottom of the message.