If you want to verify that the website you put into the Homepage field of your Friendica profile really belongs to you, you can do so using the rel-me microformat. Which basically is a machine read-able link to an URL in the internet that is also me. When to of these locations on the web that claim to belong to the same person link back to each other, it can be seen as an indicator that this person has control over these two places, thus making the claim more believe-able.
Say your Friendica nickname is happy and you created your account on the server friendica.example.com then your profile URL page is https://friendica.example.com/profile/happy. For this URL you need to add a link from your homepage by adding some HTML code1).
<a href="https://friendica.example.com/profile/happy" rel="me">This is my Friendica profile</a>
Once this is done, proceed to Step 2.
Edit your profile and add a link to the webpage where you just entered the rel-me link to your Friendica profile into the Homepage field of your profile. Then save the changes to your profile.
Friendica will now try to find the rel-me link on your homepage. If it does, it will automatically show a verification notice for your homepage link in the profile. If you have already added the link to the homepage field before performing Step 1 above, don't worry! Friendica will repeat the check for the rel-me link once a day to detect changes in the verification chain and change the display accordingly.