To obtain a Qualified Electronic Signature, a user is asked to register and verify within the ZealiD mobile app. One of the steps requires to enter a phone number and email address to register user's mobile device that will be used for qualified signing. One-time-passwords or OTP codes are received via SMS and email.
Find the list of supported phone numbers below:
| Country | Prefix |
| Albania | +355 |
| Australia | +61 |
| Austria | +43 |
| Belgium | +32 |
| Bosnia and Herzegovina | +387 |
| Bulgaria | +359 |
| China | +86 |
| Colombia | +57 |
| Croatia | +385 |
| Cyprus | +357 |
| Czech Republic | +420 |
| Denmark | +45 |
| Estonia | +372 |
| Finland | +358 |
| France | +33 |
| Germany | +49 |
| Greece | +30 |
| Hong Kong | +852 |
| Hungary | +36 |
| Iceland | +354 |
| Ireland | +353 |
| Italy | +39 |
| Latvia | +371 |
| Lithuania | +370 |
| Luxembourg | +352 |
| Macao | +853 |
| Malta | +356 |
| Montenegro | +382 |
| Netherlands | +31 |
| North Macedonia | +389 |
| Norway | +47 |
| Poland | +48 |
| Portugal | +351 |
| Romania | +40 |
| Serbia | +381 |
| Slovakia | +421 |
| Slovenia | +386 |
| South Africa | +27 |
| Spain | +34 |
| Sweden | +46 |
| Switzerland | +41 |
| Thailand | +66 |
| Turkey | +90 |
| UK | +44 |
| Ukraine | +380 |
| USA | +1 |