I have used dwi and T1 image to obtain tractagrophy networks using the iFOD2, default algorithm of tckgen command. Which files should I use with tckgen command and how can I generate those files if I want to obtain tractagrophy networks with Tensor_Det algorithm? I could not find any information. Thanks for your help in advance.

The required inputs for each tractography algorithm can be found on the tckgen documentation page. For Tensor_Det:

Tensor_Prob: A probabilistic algorithm that takes as input a 4D diffusion-weighted image (DWI) series.

So the input should be a diffusion weighted image before any fiber orientation modelling has been performed, as tensor fitting is performed as part of the tractography algorithm.

tckgen -algorithm Tensor_Det dwi.mif out.tck [options]
# Or for data in nifti format
tckgen -algorithm Tensor_Det data.nii.gz -fslgrad bvecs bvals out.tck [options]