What is important in landing page?

[Vowels]

hello there,

Landing pages are playing most important role in each marketing campaign. For each and every landing page, most important factor is,
How much user-friendly is it ?
How much time it can be take to load on device ?
Designing and how easily it can put your marketing goal to user ?
If possible, than a video, describing your marketing goal.

This is main characteristics of a landing page.

Thanks