You can have partial bitcoin just like you can have a partial dollar, however there are multiple units of measurement in a dollar representing different percentages: pennies, nickels, dimes, quarters, half dollars, silver dollars, etc.

There are not many measurements to break Bitcoin up into, so normally you just measure your wealth in percentage of Bitcoin.

The smallest (and really only other major) unit of measurement in BTC is an abstract unit called a Satoshi, one hundred-millionth of a Bitcoin. They are generally used to compare the measure of an altcoin to Bitcoin, rather than to declare wealth in bitcoin. For example, one tends to say "I have 0.00000001 bitcoin" instead of "I have 1 Satoshi", but if you're checking the price of an altcoin, you might say "That's 575 Satoshis" instead of 0.00000575 Bitcoin.

Transferring hundreds of thousands of Sats worth of Bitcoin (not even close to a single Bitcoin) is the same steps as transferring thousands of Bitcoin.