Hi @Dushyanth ,
if you are talking about entering a last name in your certification/exam profile:
Microsoft Certification / Exams is currently not supported in the Q&A forums.
Maybe one of the links is helpful:
Microsoft Training & Certification is supported on their own forums:
Microsoft Certification - Exam Registration: https://trainingsupport.microsoft.com/en-us/mcp/forum/mcp_exams-mcp_exam
Microsoft Certification - No Last Name While Registering For Exam: https://trainingsupport.microsoft.com/en-us/mcp/forum/all/no-last-name-while-registering-for-exam/4cde20dc-ef66-4aaa-8c86-48cdd1443cc8
In the last link there is the solution:
Since you mentioned that you do not have a last name, you can replace your last name with underscore (_). This will be accepted by the exam vendor as an agreement.
If your question is not related to a certification/exam profile maybe using an underscore works as well.
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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten