Yes you can, in watermark setting, go to Placement and select 'Custom'  from drop-down menu:

You will see these custom placement fields:

Using above custom placement fields, you can customize watermark position; where X Offset determines position of X co-ordinate. For example, if the value is 0, watermark would be at the very left side of the document, as the X-Offset value increases it will move towards right.

Y Offset determines position of Y co-ordinate. For example, if the value is 0, watermark would be at the very bottom of the document, as the Y-Offset value increases it will move towards top.

Width determine how wide watermark will be. If you are using large font size, consider using larger value for width. Depending on how long the watermark is you can decide value for height. 

Finally, you can choose angles for rotation from the drop down menu.

For information about other fields in watermark setting, you can find similar FAQs in our knowledge base.