The oOak tTree

It is more proper to capitalize titles.

It was very difficult to walk without pause, the two travelers want to eat, they are Once upon a time, there were two travelers. The travelers are stranded, hungry, and tired, t. They hopedsearched for food and hoped that they would find fruits, but unfortunately they didn't find anything except oaks, tan oak tree. They were unhappy,sad and suddenly it started to rain, i. In this moment, they realized that the tree was shelter, where they could rest and be safe.

This is a very long sentence. All I did was fix some errors and split it up a little bit. I recommend giving the travelers names and introducing them more. I did my best to convey your message.

Don't be ungrateful, appreciate everything around you, and then you will find your happiness.

Nice piece of advice,

The oOak tTree

It was very difficult to walk without pause, t. The two travelers wanted to eat, since they are hungry and tired, t. They hoped that they would find fruits, but unfortunately they didn't find anything exceptonly found oaks, t. They were unhappy, then it suddenly it started to rain, i. In this moment they realized that the tree was shelter, where they could rest and be safe.

I'd say to break up your sentence into many. Having too many commas or words can make a run-on sentence.
Using present and past tense words like 'want' for present and 'hoped' for past in the same story can be jarring. Try to stick to one!~

Don't be ungrateful, appreciate everything around you,. Only then you will find your happiness.

A little nit picky but separating these can add a natural flow when saying it outloud.

The oOak tTree

Title capitalization rules

It was very difficult to walk without pause, t. The two travelers wanted to eat, they awere hungry and tired, t. They hoped they would find some fruits, but unfortunately they didn't find anything except oaks, tonly found oak trees. They were unhappy, s. Suddenly it started to rain, and in this moment they realized that the tree wasprovided shelter, where they could rest and be safe.

This is far too long for one sentence, I broke it down into multiple.

Don't be ungrateful,; appreciate everything around you, t. Then you will find your happiness.