We present cosmology results combining galaxy clustering and weak gravitational lensing measured in the full six years (Y6) of observations by the Dark Energy Survey (DES) covering $$5000deg$^2$. We perform a large-scale structure analysis with galaxy samples defined from the final data extending to redshift range $z\lesssim 2$, using three two-point correlation functions (3$$2pt): (i) cosmic shear measuring correlations among the shapes of 140 million source galaxies, (ii) auto-correlations of the spatial distribution of 9 million lens galaxies, and (iii) galaxy galaxy lensing from the cross-correlation between lens positions and source shapes. We perform the analysis under a rigorous blinding protocol to prevent confirmation biases. We model the data in flat and $w$CDM cosmologies. We find consistent cosmological results from subsets of the three two-point correlation functions. Their combined analysis yields $S_8\equiv \sigma_8 (\Omega_{\rm m}/0.3)^{0.5} = 0.789^{+0.012}_{-0.012}$ and matter density $\Omega_{\rm m} = 0.333^{+0.023}_{-0.028}$ in $\Lambda$CDM (68% CL), where ${\sigma }_8$ is the clustering amplitude. The factor of two improvement in constraining power in the $\Omega_{\rm m}$–${\sigma }_8$ plane relative to DES Year 3 is due to higher source number density, extended redshift range, and improved modeling. These constraints show a (full-space) parameter difference of 1.8$\sigma$ from a combination of cosmic microwave background (CMB) primary anisotropy datasets from {} 2018, ACT-DR6, and SPT-3G DR1. Projected only into $S_8$ the difference is $2.6\sigma$. In $w$CDM the Y6 3$$2pt results yield $S_8={0.782}_{-0.020}^{+0.021}$, $\Omega_{\rm m} = 0.325^{+0.032}_{-0.035}$, and dark energy equation-of-state parameter $w=-{1.12}_{-0.20}^{+0.26}$. For the first time, we combine all DES dark-energy probes: 3$$2pt, SNe Ia, BAO and Clusters. In this combination yields a $2.8\sigma$ parameter difference from the CMB. When combining DES 3$$2ptwithothermostconstraininglow-redshiftdatasets(DESIDR2BAO,DESSNeIa,SPTclusters),wefinda2.3$$ parameter difference with CMB. A joint fit of Y6 3$$2pt,CMB,andthoselow-$z$ datasets produces the tightest $\Lambda$CDM constraints to date: $S_8={0.806}_{-0.007}^{+0.006}$, $\Omega_{\rm m} = 0.302^{+0.003}_{-0.003}$, $h={0.683}_{-0.002}^{+0.003}$, and $\sum m_{\nu }<0.14$ eV (95% CL). In $w$CDM, this dataset combination yields $w=-{0.981}_{-0.022}^{+0.021}$, with no significant preference over $\Lambda$CDM.