When Yahoo decided to reformat everything, many of our customary sites as well as functions, were changed, or eliminated.
Specifically, to "Forward"
Select "Forward" above open email
Now select from one of the underlined fields, either To, CC, or BCC (it doesn't matter for this purpose)
Up pops the "Address Book" with email addresses and nicknames,
Drag to full screen.
If you need a particular Category, select from top right (Select "Go")
Now select the field (method) for each person (I prefer BCC for privacy
If you have more than one page, just select the BCC again and select the next page and continue as before
"Insert Choices" at bottom left of screen
All of your email addresses will be in their selected field
This "Address Book" is not the same as before, certainly without all of the capabilities, but it is great for sending or forwarding emails. You can select as many as you need and are not limited to 20, as with "Contacts", which I use only for editing, adding a contact or category.
Good luck
