bash - Why does my Linux text file (created with echo) end with a newline? How can I remove it?

all experts I facing an issue with adding a new line with sed

I want to add a line into the end of the text file, I tried with

echo "Hello, how are you?" >> myfile.txt

but the issue is its creating extra one more empty line like below

 1 Hello, how are you?
 2 

so I want it will create 1 line end of the text file line if there is no line into the text file then it will create as a 1st line & all next line will create after the last line without any empty/blank line, T.I.A