If you are using the ligation sequencing kit (SQK-LSK114), regardless of the length of the DNA, 0.2 pmol of processed DNA should be taken into the sequencing adapter ligation reaction (please see the answer here for detail) in order to keep the proper ratio between adapter and DNA.

If your fragments are shorter than 3 kb, please use the short fragment buffer (SFB) in the SQK-LSK114 kit during the final wash steps to ensure these shorter fragments are not lost.