Landing page experience refers to how good we think someone’s experience will be when they get to your landing page (the web page they end up on after clicking your ad).
Every time someone does a search that triggers an ad that competes in an auction, Google calculates an Ad Rank. This calculation incorporates your bid, auction-time measurements of expected CTR, ad relevance, landing page experience, and other factors.
A major factor of this calculation is the quality of your landing page: How relevant is your landing page to the Ad copy test? Another big help is if the headline on your landing page matches closely with that of the Ad Copy.
The AdWords system visits and evaluates landing pages on a regular basis. If you’ve made significant changes to improve your landing page experience, it could lead to higher ad quality (and higher Ad Rank) over time. Ads with higher quality scores are associated with lower top of page bid estimates. That means it’s easier for your ad to show towards the top if it is of higher quality.
Go through this video to understand more: