Omnichannel is not the same as multi-channel. Multi-channel is having a physical store and an online store and a mobile app — three parallel operations that happen to belong to the same brand. Omnichannel is when the three are the same operation for the customer: the same stock, the same price, the same vouchers, the same history, the same cross-channel returns.
The modern customer accepts nothing less. They browse online and buy in store; buy online and collect in store (click-and-collect); return in store what they bought online; try on in store and buy from their smartphone on the way out. The brand that treats these moments as separate channels loses the customer to whoever treats them as a single journey.
Real omnichannel requires specific infrastructure: shared (not synchronised) stock, a unified catalogue, consistent pricing policies or explicit per-channel rules, a POS that sees the e-commerce, an e-commerce that sees the nearest stores, BI that analyses margin and behaviour by channel and by customer. MAXIRETAIL + MULTI + MyBusiness-ITV by INFOS deliver this operation without specific development.