This is the 4452nd most frequent German word.
klappen
To work out, succeed, or function properly.
In this sentence, 'klappen' is used to express the idea of something succeeding or working out as intended.
Es wird schon klappen.
It will work out.
Here, 'klappen' is used in the sense of folding objects, often in combination with a prefix like 'zusammen-'.
Der Tisch kann zusammengeklappt werden.
The table can be folded together.
In this usage, 'klappen' refers to the smooth execution or realization of events or plans.