A notary public or two unbiased witnesses should sign the document underneath the signature in question. These people need to be physically present when the document is signed.
If it is too late to have the document witnessed or notarized, you can subpoena a signature sample to create a comparison (assuming there is a court case).
you can have the real person sign their signature and compare it to the one you think got forged or ask the person who had their signature written down if they recall signing it.
i think 34 years person can get a DNA test done without a parent's signature.
To prove that the signature is a forgery, you would use expert handwriting analysis. To prove that a specific person forged your signature is a bit harder, but if you can pin down the time when the document in question was signed, there MIGHT be relevant security camera footage. Otherwise the evidence is circumstantial. If a particular person is trying to make use of this forged document (e.g., is trying to cash a forged check) then there is a reasonable presumption that he is the person who committed the forgery.
There is not a legal process for changing a person's signature. If doing so though, credit cards, driver's licenses and other proofs of identity should match the new signature to make it easier to prove it is the same person.
A notary can notarize the signature if it is signed in front of them and done in the state where the notary is licensed. Where the signing person lives does not matter.
A request for a signature verification can be done in a letter. Ask the person to verify they did or did not sign the document in question and state the date of signature.
If by "notarized" you mean taking an acknowledgment such as on a deed or mortgage or administering an oath such as on an affidavit, you cannot get it done for another person because the notary is required to personally witness the signing. If by "notarized" you mean simply attesting to the validity of a signature, you can get it done for another person, because that type of notarial act may be done based on the notary's personal knowledge or other satisfactory proof of the person's signature. For example if a notary is attesting to a signature and personally knows the person's signature, the notary may attest to the signature but may not complete an acknowledgment that the person signed it in his/her presence.
The naming of the executor is something done by the person making the will. If they are still living, they can do what they like and no signature is required.
A fraudulent signature is often referred to as a forged signature or a counterfeit signature. This occurs when someone signs a document using another person's name without their authorization or consent, which is illegal and unethical.
* Unless you have a contract of sorts stating this was a loan and a date, the amount of the loan and this person's signature along with your signature on it you can't prove this is a loan and not a gift as it would hearsay only. Without the contract, sorry but you are out the money.
A signature on the application.
Hire a handwriting expert