AMEX Offers are listed under each AMEX card in your online account. You will see them, just so that out of 100 offers, about 99 are useless!
Not all cards got the same offers. Some offers are quite useful like spend $50 in grocery stores got $10 credit, up to 5 times - this one we never see it on any of our cards including a card is for grocery shopping!
Also need to check offers frequently because the number of offers is finite - once enough cardmembers add the offers to their cards, the offer is gone. Offers for spending at Best Buy, Lowes, Staples, disappear Real Fast, as they are 10% to 25% statement credit rebate. A few weeks ago we used a $25/$100 Staples offer on each of our cards - Bought a $200 Visa Gift Card when Staples had No Activation Fee promotion, split the payment to 2x $100, each paid with a card had the Staples offer. $25 statement credit showed up 10 days after the transaction. That is like getting $200 real money with only $150 payment. The Staples offer shows up twice a year, only stays available for may be 10 hours. One time we were traveling in Asia, I saw it on several of my cards but I was too tired, decided to check it again the next morning (to decide which card to add the offer, you can only add it once). The next morning when I checked again, the offer disappeared.
Right now an NCL $125/$500 offer just shows up. I saw it 2 days ago. It expires in Mid Sept. I am hoping to see an RCL or a Carnival brands (Princess) offer. Our Mid Nov Regal Princess Transatlantic has final payment due date on Aug 19. We can use another Princess offer if it pops up!