But I don't know, maybe that works.I've been hand writing addresses and my signature. 

In your signature (and don't get mad at me please, if this sound horrible, sorry) if you can use a more common name than La'Keita, maybe a nick name, you'll find a lot better results. 

Tenant makes this certificate for the benefit and protection of Lender with the understandingthat Lender intends to materially rely on this certificate in making a loan on subject property.OWNER TENANT(Signature)( )Phone Date (Printed Name)( )(Phone Number) DateIf leaving insurance on the property (I never do) get this notarized Assignment of Beneficial Interest of Insurance Proceeds to YOUR COMPANY OR YOU, YOUR ADDRESSI, SELLER, as beneficiary and claimant to the insurance policy # POLICY NUMBER with INSURANCE COMPANY: do hereby authorize and direct INSURANCE COMPANY to pay to YOUR COMPANY OR YOU, YOUR ADDRESS the total sum of All Proceeds of the aforementioned policy(ies).I understand, the proceeds I have authorized to be paid to the above party will be in lieu of payment to me, as specified in the above policy or policies.

By his/her signature herein below, Seller specifically agrees to the provision stated in this paragraph: (1) Buyer may cancel this Agreement, (2) Buyer may insist upon the specific performance of the Seller under this Agreement, or (3) Buyer shall be entitled to receive from Seller a total sum of $50,000 or 25 percent of the contractual price, whichever one is greater.

Today  I found a letter from the USPS ( Post Office) in my mail box offering some new services amount which "street addressing" and "signature on file".

But the cost includes the envelope, postage, my logo, my signature, everything.

Let me rephrase this - your signature on the P&S comes with responsibility to perform,  which is a function of closing on the purchase if need be, even if that is not your primary intention...Where I have an issue, is all of the wholesaler running around, loading contracts with out clauses, without any intention to perform as per their signature should they be unable to find a retailer...this is unethical indeed!  

I'm wondering how I should do my signature on emails.

Here I was thinking that I had done my due diligence by poking around the personal website you have in your signature prior to posting; when in reality I essentially just did the door-hanger equivalent to asking bill gates if he is affiliated with a computer company.  

@Claire Trammell, your signature says you work for Yellowletters.com, yes?