Thanks for every suggestion and advises.
Finally, the work is done and come back here for leaving some conclusion for everyone further reference.
Follow the previous situation description, first has to format the data content from pdf to excel for further data fetching.
However, due to the data source was converted from PDF to Excel, the content didn’t group as a Data Table which means without Table name I can’t use “Get Table Range” activity to know the range of specific data content from the excel file(It also separated to several sheets), otherwise I can write back the formatted data to the right place(particular cell).
Hence, I decided to fetch the data from each cell of each row. Everytime I fetch a cell and store as a List(of string), consider of the content range might be dynamic in the future, to store and know how long does the Data Table is. After it deal with one row, it write List into a temperate DT.
The first point is to make sure to initiate the variables, not only List(I only did this before @KarthikByggari @amarasto mentioned, thank you so much, I appreciated it.) but also DT.
The second point is, I declare the DT at default without given specific columns since I don’t know the exact range, it’s the reason why it came out error “Add Data Row: Input array is longer than the number of columns in this table.”
Make sure no matter know how large the range is or not, it needs to “add Data Column” before using “Add Data Row”.
Thank you @Vashisht for advice, I did the same as you said at first, but it didn’t work probably because of w/o “add Data Column”.
Really thank you guys for helping me overcome this issue.