Some popular exchanges, like Binance for example, ask that you include a very specific memo in order to have your account credited.
If you forget to do so, providing them with the onchain transaction ID might help. To retrieve this, follow these steps:
Go to www.stellarchain.io
Enter your wallet address in the box at the top (to find your Sendana wallet address, select "Wallet Address" from the left-hand menu in the Sendana web app)
After entering your wallet address on Stellar Chain Explorer, click on "Operations" to view your recent onchain transactions
Click on the relevant transaction and copy the long 64-digit transaction ID you see at the top
Share that ID with the exchange.
It's a good idea to screenshot that transaction page too. The recovery form on Binance or similar exchanges will generally ask for proof from the sending side, and an explorer page showing all the details in one view usually satisfies it.
Going forward, always try to remember to include the required memo whenever transferring to one of these exchanges. This will save you a lot of time.