You can find and download the user manual for the Tefal Latitude 30 travel iron from this Tefal web page:
Scroll down on that web page to near the bottom. There you should see a heading for Travel Iron and an icon and link for Latitude. Click or tap on the Latitude link.
That will bring you to the Tefal web page for Tefal LATITUDE User Manuals:
On that web page in the section headed Instructions and Manual (with an icon for Warranty Information) you should see a search box with a drop down menu and the direction "Choose a language for displaying the instructions and user manuals:" Click or tap on the downward pointing arrow on the right end of the search box and choose the language you want for the manual.
A Download Manual icon will appear. Click or tap on it.
Then, you will see the PDF document for the user manual. You will need Adobe Acrobat Reader (free) software.
The first illustration of the iron you should see in the manual indicated where the Water Tank Filler cap is located near the tip of the iron handle. The water tank is within the handle.