this will depend on your data. however, the general solution is to apply the date function with the format you want:
load .... date(INPUTFIELD, 'YOUR DATE FORMAT HERE')
Qlik will attemp to interpret your input data automatically. however, depending on the data you may need to parse it. for example if you are loading from different sourcese and the date fields are in different formats, say some of your input date is in MM-DD-YYYY and Qlik cant automatically load it (this is just for illustration as you need to test your data). you will need to parse it like
date(subfield(Field,'-',1) & '/' & subfield(Field,'-',2) & '/' & subfield(Field,'-',3), 'MM/DD/YYYY')
or
date(replace(Field,'-','/'), 'MM/DD/YYYY')
assuming your date format is MM/DD/YYYY
you need to take a look at your data and apply whatever string function you need
