Question: If your principal customers are other companies you can start with the question of whether it is the customers or you yourselves that determine the products design and function
Please fix the punctuation.
Fixed: [If your principal customers are other companies, you can start with the question of whether it is the customers or you yourselves that determine the product's design and function.]

Question: The strongest joint on the market
Please fix the punctuation.
Fixed: [ The strongest joint on the market]

Question: Bus trips to places of interest the Baltic and the North Sea musicals
Please fix the punctuation.
Fixed: [Bus trips to places of interest, the Baltic and the North Sea, musicals...]

Question: This text was in all probability copied from Jakob van Melle At the back of the book were eight copper engravings glued together showing the dance together with new High German text from 1701
Please fix the punctuation.
Fixed:
[This text was in all probability copied from Jakob van Melle. At the back of the book were eight copper engravings glued together showing the dance together with "new" High German text from 1701.]