How to format the date in xslt?

This will probably help: ms:format-date Function

Using the example from the article you can format a date as follows:

Date Unedited: 2000-02-16T15:56:00

Date Edited: Feb 16, 2000

If you are using XSLT 1.0, you might find the date formatting features in EXSLT - Date and Times useful, in particular format-date. If you are using XSLT 2.0, you can use the built-in function described in Formatting Dates and Times.

As en example of the latter, if you want to output a date on the format "Jan 01, 2020", you'd write

<xsl:value-of select="format-date($d, '[MNn,*-3] [D01], [Y0001]')"/>