How can I remove introns from a feature to obtain the cDNA sequence?
Select the Feature

In Map, Sequence, or Features view, click to select a feature that contains introns.
Splice to Remove Introns

To remove introns from the feature, click Features → Introns → Splice to Remove Introns... .

If desired, adjust the file name of the new sequence. To merge the segments from the original feature, click the check box. When you are ready to make the new file, click Splice.
View the Sequence

If the segments were merged, you will see a seamless spliced feature.

If the segments are not merged then a segmented feature will be created and the former intron boundaries will be visible as lines in Map or Sequence view.