The IRS needs two copies.

One goes with the tax return.  That one can be (a) e-filed as a PDF with the rest of the tax return, (b) e-file the tax return and mail the 3115 with Form 8453, or (c) mail the entire tax return with Form 3115.  The instructions say this one does not need to be signed, but I would have it signed anyways.  It also says it must be an "original", which puts into question if it should be attached as a PDF, but the IRS specifically allows 3115 attachments to the tax return so it should be fine.

The second copy is mailed to a different address by itself.

https://www.irs.gov/instructions/i3115#idm140516454118016