In ,
There are various options, and there have been threads here on sheds
and shed bases before. Possibilities:

Concrete blocks/bricks, bedded down on sand and cement and the shed
supported on that (I did this with shed posts laid crossways and then
the shed on top of that.

Slabs laid to form a base

Ditto but with concrete.


Plus:

Timber bearers on gravel over a water permeable weed blocking fabric over
levelled ground.

pk