Often, you will have PDF files where the text in one cell overflows into an adjacent cell, like this:
If you want the data to merge into a single cell, go to Options > Conversion and select "Merge cells with overflowing text".
This will move the data into a single cell.
Note that the position of the column divider in relation to the the text will determine where to place the data. You may need to reposition the divider until the data is in the correct column.
The key is to get the majority of the data in the correct cell - if you have some cells that merge into the wrong column, you may need to correct these manually in your output.