Captive portal

The page people see when they join your MikroTik hotspot. Save, use the Download login.html button on the panel head, upload the file to the router's hotspot folder (Files > hotspot), and in the hotspot server profile allow "HTTP PAP" login. Download it again after every change.

Where
Settings → Customer portal (Captive portal panel)
Who can change it
ISP details
Captive portal (Settings, Customer portal tab)
Captive portal (Settings, Customer portal tab)

The settings

Title

Text

Shown at the top of the hotspot page.

Default
the ISP's name (max 80 characters)
When to change
To change the heading.

Message

Text

A short message under the title.

Default
empty (max 400 characters)
When to change
For notices such as support hours.

Help phone

Text

Shown as "Help: <number>" at the bottom of the hotspot page.

Default
empty (max 30 characters)
When to change
So customers can call you.