For the ZF 8HP automatic transmission (a $10,000 unit if it fails), BMW calls it "lifetime fill." The service manual, however, contains the procedure for "Oil change in automatic transmission"—because even ZF recommends fluid changes at 60,000 miles. The manual specifies the oil temperature must be between 30°C and 50°C when checking the fill level. Do it cold, and you will under-fill it.
For the serious DIYer, accessing a digital copy of the OEM (often run via a diagnostic interface like ENET cable and a laptop) provides the highest level of detail. It tells you exactly which tools you need, the labor time expected, and the exact part numbers. Bmw F11 Service Manual
Don't work on your F11 blind. Get the manual, read the procedure twice, torque it to spec, and enjoy the ultimate driving machine for years to come. For the ZF 8HP automatic transmission (a $10,000