Items not standard everytime I order

Items not standard everytime I order

Hi, 
I have a problem and not sure how to solve this.
We run a small clothing business - what it means is that we have items that are very different, provided by multiple providers etc... Hence there will be 10000 type of items.
When we raise the bill, we need to add the items. How we can do it best.
Imagine we receive a bill in PDF format for number of SKU's - then we want to load them on our POS. What is the best way to add the items.