i cannot update my software

Please don't make us guess--what iPad? Older models have hardware limitations that prevents them from being upgraded to current OS versions, but you've not told us the model.

Do Settings > General > About. Find and post the model number BUT NOT the serial number:

My simple and generalised answer is to your vague question is your iPad is too old and too underpowered to be upgraded/updated any farther.

Time to consider a new or discounted, refurbished iPad from Apple.