There are several reasons your outbound text messages may get split into multiple messages.
It is longer than 160 characters
Text messages support a maximum of 160 characters, so if you send a text message longer than that, LeadSimple will split it into multiple messages.
It contains characters that are not GSM-7 compliant
If you paste your message from a Microsoft Word document or text editor, it may include symbols that are not part of the text messaging standard alphabet.
For technical reasons, these non-compliant characters limit your text message to a maximum of 67 characters. Any more than that, and your message will be split into multiple messages.
LeadSimple will warn you about these non-compliant characters, so you can decide whether to replace them before sending your message.