Thanks ATpoint! I think I can get the gtf file at: https://cf.10xgenomics.com/supp/cell-exp/refdata-gex-GRCh38-2020-A.tar.gz but velocyto also need repeat_msk.gtf which I don't know how to get after reading 10x website. Would you please have a suggestion?
velocyto run10x -m repeat_msk.gtf mypath/sample01 somepath/refdata-cellranger-mm10-1.2.0/genes/genes.gtf