Step by Step:

Send a file with your email message by adding an attachment.

Add an attachment

Select Home >New Email.
Or, for an existing email, select Reply/Reply All or Forward.
Select Home >Attach File, and choose an option:
- Recent items - select a file from the list of the files you have saved or worked with recently. These files could be saved locally, or they might exist on internal network locations and Group Files.
- Browse Web Locations - select files from OneDrive, SharePoint sites, or Group Files that you have accessed earlier.
  NOTE: By default, recipients have permission to edit the attachment, but you can override this before sending the attachment. To change the permissions, see Manage the items attached to an email.
- Browse This PC - select a file from your local computer.
- Outlook Item - attach an email message as text or as an attachment.
- Business Card - attach an electronic business card to the message.
- Calendar - insert a calendar, with specific date range and other details.
- Signature - add your signature to the message.
To attach an item, select Attach Item, and then select one of the following options:
You can see the size of an attached file and its name if you hover your mouse cursor over it. If you want to remove an attached file, select the down arrow, and then select Remove Attachment in the drop-down list.