There are a number of different areas of the system where you are able to attach a file this depends on where you are in the system and what you would like to do.
You can attach a file to a contact or organisation record or if you want to send one to an individual contact record or to a bulk group of contacts. Before you attach a file to these different areas, you must remember to upload the document in to the system to begin with.
Here are some relevant documents:
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