ohh! I have got it. There is an editable option.

Better to edit your fasta headers before you make tree.

Thank you so much for response. Actually, I missed the editable option first. Now, I've got it.

Thanks again.

I think you mean "leaf labels" or "tip labels". The nodes are the branch points in the tree. I like to download the FASTA alignment from BLAST, or download the BLAST hits and then perform a better alignment using MAFFT, MUSCLE or other multiple alignment software. Then I view the alignment with AliView (free for MACs) or BioEdit (free for Windows) and adjust the alignment, if needed using these multiple sequence alignment editor tools. It is always good to look at your alignment carefully because there are many things that can go wrong.

Then, you can re-name the sequences using the SNAD Sequence Name Annotation Designer https://veb.lumc.nl/SNAD/

After this, I often use Microsoft WORD or another text editor, to find/replace or copy/paste to "fix up" the names a little more. It is often necessary to replace spaces with underscore, and remove any special characters such as "(" or ":" that are in the names.

Then move on to build a phylogenetic tree using IQ-tree, or RAXML, or MEGA or PAUP or whatever tree building software you like. It's often useful to do a quick neighbor-joining tree to get an idea of what you are dealing with, before using tools that take a bit longer to run.

http://www.iqtree.org/

https://www.phylo.org/

etc...