Before a tariff is imposed, the seller sells the good for $10 and keeps $10 in revenue.
If a tariff of $1 is imposed under these hypothetical circumstances, does the buyer pay more? Does the exporter get paid the same as before?
Clearly, it's neither guaranteed that the buyer will "pay more" nor that the export will "get paid the same as before". In reality because demand is neither 100% elastic nor 100% inelastic, what tends to happen is that the cost of the tariff is split in some ratio between the buyer and seller.
I find it mildly amusing that there are so many people claiming that it's 100% on one side or other, when it's trivially easy to see why that can't be GUARANTEED TO BE the case.