If your text file contains only dialogue with no time information, the primary challenge is . You cannot simply "save as" SRT, because the video player will not know when to display the text. You must manually synchronize the text to the video.
If you already have a transcript, free online tools can automate the formatting or simply convert the file extension. GoTranscript Subtitle Converter : Upload your TXT, select as the output format, and click convert. MConverter how to convert txt to srt file