Is it possible to import tag items from an excel file

I understand your request, that you need some guiding and assistance for importing text data from a text file, which has data lines with the TAB character as the field separator character.

A simple test can help to understand, why the TAB character is not the very best applicable character when working with Mp3tag.

You can create your own test text import file, using the Windows Notepad editor.
Step1: Open Notepad, then type ...
1[Tab]2[Tab]3[Enter]4[Tab]5[Tab]6[Enter]7[Tab]8[Tab]9[Enter]
... then save these just created three lines into text file with a name of your wish.

Step2: In Mp3tag select three dummy media test files.

Step3: Use the previously created text file as input for ...
Mp3tagConverter "Textfile-Tag" ...

Formatstring: %F1%%F2%%F3%
<!--coloro:#000000--><span style="color:#000000"><!--/coloro-->^    ^<!--colorc--></span><!--/colorc-->
<!--coloro:#000000--><span style="color:#000000"><!--/coloro-->here here insert tab character<!--colorc--></span><!--/colorc--> <!--coloro:#dd0000--><span style="color:#dd0000"><!--/coloro-->[<!--colorc--></span><!--/colorc--><!--coloro:#000000--><span style="color:#000000"><!--/coloro-->Alt+009<!--colorc--></span><!--/colorc--><!--coloro:#dd0000--><span style="color:#dd0000"><!--/coloro-->]<!--colorc--></span><!--/colorc-->
or insert a tab character from the clipboard

The converter should create tag-fields F1, F2, F3 within the dummy media test files.

File 1:

F1=1
F2=2
F3=3

File 2:
F1=4
F2=5
F3=6

File 3:
F1=7
F2=8
F3=9

Step4: Use dialog "Extended tags..." to check the tag-fields and their content, ...
which must be the data from the test text file.

You should have recognized, that the data import works, even when the data separator is the tab character.
But applying this procedure each time, with the tab character as separator, is not so useful in practice.

Better you apply some other separator character or string, which is unique within the import text file.
This will make the import process to be better automated.
Follow the convention of CSV Comma Separated Values or SSV Semicolon Separated Values or whatever own made convention you want.
Mp3tag supports what you dictate.

DD.20150308.1449.CET, DD.20150308.1955.CET