I am doing a friends taxes and I would like to know in advance the information I will need from her including credits, etc. Basically a list of credits available?

You will need all of the tax documents she has received for the year that report income and deductions.  For example, you will need all forms reporting wages, self-employed income, retirement plan distributions, interest income, dividend income, capital gain transactions, and any other applicable income documents.  

For deductions, you will need information about any dependents supported by the taxpayer.  This information includes the dependent's name, date of birth, Social Security number, and information about how long they lived in the household during the year.  If the dependent is a student, you will need their Form 1098-T reporting college tuition payments.

Some of the most common credits will be generated on the return based on the information entered from the income documents (Saver's credit) or the details about the dependent(s) (Child Tax Credit, Earned Income Tax Credit, Education Credits).  

Using TurboTax Online, your work will be saved along the way, so that if you need to get more information from your friend, you will not lose the work you have already entered.