Add a name in the header bar

In my site : https://locationvoiture.touracancun.com

You can see some page as this one : https://locationvoiture.touracancun.com/assurances/

With an empty yellow header, I desire to set the name of each page. In this case : Assurances

I have 3 page where I need to set the correct name :

1) https://locationvoiture.touracancun.com/conditions-generales/

– Conditions Générales

2) https://locationvoiture.touracancun.com/assurances/

– Assurances

3) https://locationvoiture.touracancun.com/concours-mensuel/

– Concours Mensuel

How can I do it ?

Cheers