You have two options to create a will in Texas. You can create it on your own and sign it, or you can create a formal one with an attorney that you sign in front of witnesses. The will you create on your own is a holographic will.
The State Bar of Texas explains a holographic will is much easier to create, but it poses issues when it comes to validating the document in probate. Specifically, your signature plays an important role in this type of document. When you do not have witnesses who can attest that you signed the document of your own free will and that the signature is indeed yours, it can open the door for someone to say the will is a fake.
For a formal will, you must have at least two witnesses who are over the age of 14 watch you sign your will and then sign the document as well. These two people can help during probate as witnesses who will tell the court they saw you sign the document. It is incredibly difficult for someone else to prove these witnesses are not telling the truth, so your will is likely to stand up to scrutiny.
It is essential that your signature is in your own writing. Essentially, you have to sign your name in the way you normally do to the document. If you do not do that, it can also create issues in probate as someone could provide evidence that this is not your legal signature. This is something that having a formal will can avoid because even if your signature is not normal for whatever reason, the witness testimony will still validate it.