Sometimes, creators distribute a ZIP file that contains the MCPACK file inside it, rather than the ZIP being the MCPACK file. This is common on sites like CurseForge or Planet Minecraft.
If you see a folder containing manifest.json and texture files:
Direct file transfers (email attachments, WhatsApp, Telegram) often block .mcpack files as "dangerous" or compress them back into .zip. A direct download link:
Once you have yourpack.mcpack, create a link so others can download and open it.