Almost 77% of emails are read on phone, so if the subject line is too long, it would get cropped. The reader might overlook essential counsel or will be disinterested to read the complete thing. So, it is recommended to keep field lines within 50 characters so that they read the entire discipline. Think concerning the words which matter the most and exclude useless details.
For examples, instead of writing ‘Order No XXXX is being processed’, that you would be able to simply write ‘Your order is being processed. ’ Also, words like ‘Update’ or ‘Newsletter’ could be prevented as readers are likely to ignore such emails. Also be concise as recipients will not take much time to read. For example, use ‘Increase your sales by 60%’ rather than ‘How to augment your sales’.