How do I go from Tiff to Jpeg

Control-click on the TIFF, select "Edit With" from the drop down menu, select Preview. Once it opens, hold the option key and select "Save As…" from the File menu, change the Format: to JPEG, click Save.

Quite a few of us are old. 😎

While in Photos, right or control click on the Tiff file you want to change. See…

Yes there is as I explained up there ↑

"select Preview. Once it opens, hold the option key and select "Save As…"

from the File menu, change the Format: to JPEG, click Save."

Do you mean after you changed it from TIFF to JPEG?

You're welcome. However, a TIFF file will not automagically change to a JPEG by moving it to the Desktop or adding it to Mail.